


Just a Little Boy

by AJ_Pastel_Punk



Series: The Adorable Adventures of Spencer and Little Derek [3]
Category: Criminal Minds (US TV)
Genre: Age Regression/De-Aging, Caregiver Spencer Reid, Cuddling & Snuggling, Emotional Hurt/Comfort, M/M, Non-Sexual Age Play, Spencer Reid is a good boyfriend, agere, little Derek Morgan
Language: English
Status: Completed
Published: 2020-04-03
Updated: 2020-05-07
Packaged: 2021-03-01 01:09:06
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,077
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23456815
Author URL: https://archiveofourown.org/users/AJ_Pastel_Punk/pseuds/AJ_Pastel_Punk
Summary: Spencer starts to notice some little things about his boyfriend.A.K.A The story of how Spencer first met little Derek
Relationships: Derek Morgan & Spencer Reid, Derek Morgan/Spencer Reid
Series: The Adorable Adventures of Spencer and Little Derek [3]
Series URL: https://archiveofourown.org/series/1685974
Comments: 12
Kudos: 184





	1. Little Things

**Author's Note:**

> Some of this first chapter isn't quite as cute and fluffy as my other works in the series but it will get better. I'm not sure how many parts there will be in this but I'm think about three right now.

Spencer and Derek had been dating for a few months when Spencer started to notice it. He'd only been staying with Derek for a couple of weeks when he first saw it. He wasn't sure if Derek knew he was doing it.

The first time he could say that he really noticed it they had been watching a movie together late at night. Spencer had always been bigger on cuddles, though Derek never minded cuddling. On that night though it was Derek who cuddled up to Spencer during the movie, allowing his boyfriend to wrap his arms around his body.

Spencer could feel Derek's body completely relax against his, signaling that the other man had fallen asleep. He gave Derek a gentle kiss on the forehead and held him closer to his body. Derek, seemingly instinctively, grabbed onto Spencer's shirt.

There was nothing hars or desperate in Derek's grip. He wasn't trying to cling to Spencer like some nightmares lead him to do. He wasn't angry and Spencer's shirt just happened to get caught when he clenched his fist. Derek's grip was gentle, like all he was doing was trying to have more contact with his boyfriend.

"Goodnight Derek." Spencer whispered, once again kissing Derek's forehead.

After that he started to notice more of those little things. The little things that Derek did, but only sometimes. He'd do one or two of those little things after a few of their hard cases. Spencer couldn't explain why it only happened after hard cases, or why it didn't happen after every hard case, but he never felt the need to ask.

Spencer noticed that Derek had a strange attachment to a certain blanket they had in the closet. He had never mentioned it before, so Spencer didn't know why he had suddenly become so attached to it. The blanket wasn't bad in anyway it was just new.

It had started off simple. If they were going to watch a movie Derek would always grab the plush blue blanket that had been stowed away in the back of closet. After a few weeks of the blanket making a few appearances on movie night Derek started wrapping it around himself when he and Spencer sat in bed together. Spencer never dared to say anything. He found it adorable to see his boyfriend all bundled up in the fuzzy blanket and if he mentioned it Derek would likely stop.

Clooney seemed to notice these little things as well. If Spencer didn't notice one of those small things he would notice Clooney. The way the dog followed Derek around more closely and acted more protective than usual.When ever Derek got in that mood where he would let these little things slip Clooney was gentler with him. He would never hurt Derek, but normally the dog would be willing to rough house a bit with his owner.

Derek acted differently with Clooney too. Just like he had with Spencer he got very cuddly with the dog. Sometimes opting to sit on the floor instead of on the couch so he could sit with Clooney. Then he started to let Clooney sleep on the bed more. It used to be a rare occasion for the dog to be allowed on the bed, but Spencer didn't mind the more frequent visits of the third body.

There had been a few times where Derek spoke in incomplete sentences or slurred his words, without any help from alcohol. Those could always be chalked up to him being too tired to properly form the words and sentences. There was one time where it wasn't slurred words or broken sentences that had caught Spencer's attention.

They were laying in bed together. Spencer was reading a book while cuddling his boyfriend who sat silent the entire time. He was caught by surprise when Derek spoke. They'd both been silent for so long that he hadn't expected anything to be said.

Derek's voice was quiet and soft. Much different from any other way Spencer had heard him talk before. He heard him talk softly to scared children, Derek would talk to him the same way to comfort him when ever he has a nightmare. Though it's not as common as his strong, confident voice he'd heard Derek speak that quietly countless times. This time though, this time was different. There was something in his voice that Spencer couldn't Identify at first that just made it different somehow.

Derek let out a quiet, "I wuv you Spencer."

Spencer didn't say anything about Derek's mispronunciation of the letter L. His focus was more on the way Derek had spoke. That thing lingering in his words that Spencer just couldn't pinpoint.

Spencer just replied with a simple and sweet, "I love you too Derek."

Derek smiled back at his boyfriend. That was when it hit Spencer like a ton of bricks. The difference in his voice. That thing that had been laced into Derek's words. It was a simple innocence. An innocence that they had both lost long ago.

On occasion Spencer had seen Derek bite his knuckles after stressful cases. He wouldn't just chew on anything, it was always be his fingers or knuckles. The were a few times where he more sucked on his knuckles than chewed on him.

This wasn't something that Spencer could ignore like he could the other things. It hadn't been a terrible thing at first but it still wasn't particularly good. Then it became something bad after a particularly hard case for Derek.

Spencer can remember it exactly. They'd been sitting on the couch together when Derek started biting his knuckle, he hadn't even noticed he was doing.

"Derek? Did you hear me?" Spencer asked.

The question got Derek to snap back to reality. He noticed Spencer staring at the hand he had up to his mouth and promptly pulled it away. That was where Spencer saw the blood. He grabbed his boyfriend's hand to inspect it.

"You're bleeding. Derek you can't do that you're hurting yourself." Spencer's voice was firm but not harsh.

Then Derek got this look. His face dropped, he seemed disappointed in himself. But it wasn't the look he normally had when he was disappointed in himself. It was the look of a little kid when their parent scolds then for something they know is bad.

A tear slid down his cheek. Derek always tried not cry, and when he did it wasn't about things like this. He wouldn't cry over the things Spencer had said, he wouldn't cry over a little blood on his knuckles. In that moment Derek wasn't in his normal frame of mind.

Spencer tried his best to calm Derek, "It's okay Der. Let's just go wash it off then we can watch a movie." Derek just shook his head no, "I could read to you instead?" Spencer suggested.

Derek still didn't say anything, he just shook his head again. Spencer didn't know what to do. Something was going on with Derek but Spencer didn't know how to handle it or what it even was.

Spencer got up to grab the first aid kit for Derek. When he got back his boyfriend was gone. He noticed the bathroom door was closed. The door knob only jiggled slightly when Spencer tested it.

"Derek?" Spencer knocked on the door softly hoping to not startle Derek.

"G-go away." Derek mumbled.

Spencer sighed, "Alright baby. I'm going to my apartment tonight, okay? I'm going to leave the first aid kit outside of the door." He waited but their was no reply, "Please text or call if you need me."

Spencer didn't want to leave his boyfriend alone especially not now, but Derek needed his space. It was much lonelier at his own apartment, no dog to keep him company, and no boyfriend to cuddle. The only up that Spencer could find was that he had nothing to distract him from his research. It didn't take long to find what he had been looking for.

Age-play had been the first promising result he found. A kink, often paired with a mommy and/or daddy kink. A form of roleplaying in which an individual acts or treats another as if they were a different age. Though it could be non-sexual it didn't seem exactly right.

Then Spencer found Age regression. When a person retreats to a younger mindset. It can be a coping mechanism to help them relax and eliminate stress. It could even be involuntary in some cases. That seemed like what he was looking for.

He didn't allow himself to jump to conclusions. Tomorrow he and Derek were going to have a talk. Spencer needed to know what was going on, not because he had a problem with any of the possibilities he'd discovered, simply because he was worried about his boyfriend.


	2. Little Talk

Spencer knocked on Derek's front door just after seven thirty. Clooney's bark echoed through the house. He was standing outside for a few minutes before Derek opened the door. His eyes fell to Derek's hand, he hadn't even put a bandaid in it. Derek's second knuckle had obviously gone through the same thing as the first after Spencer had left.

"Hey." Spencer finally spoke, offering a soft smile.

"Hey." Derek replied.

Spencer's heart broke a little when he heard how hoarse his voice was, "Can I come in?"

"Yeah." Derek nodded.

"Are you okay? How's your hand?" Spencer asked, grabbing his boyfriend's hand.

"I'm fine. My hand is fine too." Derek answered, pulling his hand back.

Spencer took a deep breath, "Der, we need to talk about what happened last night."

Derek frowned, "I'm sorry about that. You didn't have to leave. You could have stayed if you'd wanted."

"You needed some space, I understand that." Spencer sighed, "But that's not what I wanted to talk about." He added.

Derek sat down on the couch, avoiding Spencer's gaze, "I don't want to talk about it right now."

"We can't just avoid this." Spencer quickly replied.

"Please, Baby, not now." Derek begged.

Spencer was ready to discuss this now, he hated seeing Derek like this. If there was someway he could help he needed to know how. Derek wasn't ready. Whatever it was Derek couldn't bring himself to talk about it yet. He could wait, if Derek wasn't quite ready yet then he could wait.

"Okay. If we aren't going to talk can we cuddle for awhile? We won't have much time for that tomorrow." Spencer sat down next to his boyfriend, scooting as close as he could get with out being on top of him.

Derek smiled, "Yeah. Let's cuddle, Pretty Boy."

That night when Derek was asleep Spencer found himself looking further into age regression, primarily what regressors typically liked. He didn't know what age Derek would be if it turns out he is little so he looked into everything. Every time he saw the pacifiers he thought of Derek, when he broke skin on his hand from his simple anxious habit.

Spencer knew he shouldn't have ordered it, he and Derek hadn't even talked yet. When he saw it he just couldn't help himself. It was just a pacifier. It wouldn't arrive for a couple of days anyway. They would have talked by then.

Spencer finally closed the laptop and cuddled up to his boyfriend. Derek, still asleep, wrapped his arms around the younger man. Spencer smiled and relaxed in Derek's arms. He was warm and safe, it wasn't long before he too fell asleep.

Derek woke up to the alarm clock going off in his ear. He quickly turned it off and looked over at Spencer. The younger man was still asleep and Derek decided to keep it that way for the time being. He kissed his boyfriend's forehead then climbed out of bed to make breakfast.

Derek had just finished breakfast when Spencer walked into the kitchen. He loved his boyfriend's sleepy expression and birds nest of hair. It always made his morning that much better. Spencer walked over to his lover and rested his head on Derek's strong shoulder.

"You awake yet Pretty Boy?" Derek laughed when heard Spencer grumble something against his shoulder, "I'll make you some coffee. Sit down and have some breakfast."

"I love you." Spencer hummed and kissed Derek's lips.

"I love you too." Derek smiled.

When they left for work they took separate vehicles. They were almost certain the team knew about their relationship but if they didn't they weren't going to try to give them any hints. So like always they drove on their own.

They had only been at work ten minutes when they were called into the conference room for a case. They were flown to California less than an hour later. They spent the whole week there on the case.

When they got home on Friday Spencer couldn't wait any longer. He and Derek needed to talk. Derek still didn't want to talk, he could tell. But if he let Derek keep pushing it off then they would never talk about it.

"Derek can we talk now?" Spencer tried to start the conversation not even five minutes after they got back to the house.

"We just got home, let's just go to bed."  
Derek suggested.

"Derek we need to talk about what happened. You can't keep avoiding this." Spencer stopped Derek before he could walk back to their bedroom.

"Alright." Derek finally agreed.

"You've been doing certain things. They aren't bad per-say, but thy seem childlike." Spencer explained.

Derek looked down, "I know."

"Do you know why you've been doing these things?" Spencer asked, receiving a nod in response, "I did some research on my own so that I wouldn't be coming into this conversation blindly. I found something in particular, if I'm wrong then I'm sorry. Are you an age regressor?"

Derek got this look on his face, as if he were trying to hold back tears, "I'm sorry. I never meant for you to find out. I just-"

Spencer hugged Derek, "You don't have to apologize. I've done my research on it. I know it's not a bad thing."

Spencer just held Derek tightly. Derek clung to Spencer and started silently crying into his shoulder. He didn't know why he was crying but he couldn't stop. He didn't want to cry, he hadn't even realized he needed to until he felt the tears dampening Spencer's shirt.

Eventually, Derek broke off the hug and sniffled. He looked away from Spencer, not wanting to confront this any further. Of course Spencer was not pleased with that. He gently turned Derek's head back to face him and wiped the tears off his cheeks. Every touch was soft and comforting, almost bringing Derek back to tears.

"Does being little help you?" Spencer asked softly, "Does it make you happy?"

"Yeah." Derek nodded.

"Then I want you to do it, and I want to help." Spencer smiled and kissed Derek's forehead, "Would that be okay with you?"

"Yeah. I think I'd like that." Derek replied.

Spencer remembered looking at little gear online earlier in the week, "Do you have any items for when you regress?"

"No." Derek admitted, "I think I'd like some though."

"Well, then we'd better start looking."

Spencer and Derek retreated to their room, soon joined on their bed by Clooney. Derek found himself more interested in petting the dog than looking at the computer, at least at first. When Spencer spoke up with another important question Derek remembered that they hadn't just come to pet the dog.

"What would you say your age range is?" Spencer asked.

Derek looked up, he had to think for a minute but eventually answered, "Three? Maybe, I don't know."

"That's alright." Spencer assured him, "Do you know what kind of stuff you might like?"

"Um, maybe a sippy cup." Derek mumbled, slightly embarrassed, "I spill stuff a lot."

"I could pick some up from the store tomorrow so we don't have to wait for it to arrive. Der, would you be interested in a pacifier? I don't want you chewing on your fingers anymore." Spencer explained.

Derek didn't even have to think, he just nodded excitedly. Spencer pulled up a website and invited Derek to come look over the items. Only a minute into their search Derek pointed to a plain blue pacifier.

Spencer was hoping he wouldn't chose that one, "Are you sure you want that one? You don't want two of the same pacifiers, do you?" Derek just gave Spencer a very confused expression, "I may have gotten a little excited and ordered this a few days ago. That's why I couldn't let you check the mail today."

Spencer handed Derek a small box. Derek struggled to open it, but managed to get it done on his own. He almost squealed when he saw the blue pacifier. He looked over at Spencer with a big smile, then looked back at the box.

Spencer laughed a bit, "It's for you Der, you can use it if you want."

With that assurance Derek popped the pacifier into his mouth. He leaned over and hugged Spencer. He loved Spencer so much, he always knew what Derek needed before Derek even knew himself.

"Thank you." Derek smiled.


	3. Little Trip

Derek was the first to wake up that morning. He felt the silicone from the pacifier in his mouth. It confused him at first, then he remembered what had happened that previous night. Spencer knew, he knew that Derek was an age regressor. He still loved Derek. He even bought him a paci.

Derek couldn't help but smile while thinking about it.

He couldn't control this completely. He could tell when it was coming most of the time and could take steps to stop it, but it was mostly involuntary. If Spencer had left him because of something out of his control he'd be crushed.

But he was happy. Spencer was still there and Spencer still loved him.

Derek crawled over to where Spencer was laying in the bed, "Spencer?" He pouted around his paci when the man didn't wake up, "Spencer. Up."

"Wha? I'm up, I'm awake." Spencer yawned.

"Hi Spencer." Derek giggled at his new caregiver's sleepy expression.

A wave of joy washed over Spencer when he saw Derek using the pacifier he'd bought, "Hi Buddy." he smiled, "You're awake early."

It wasn't really early, just early for a Saturday. After all that had happened the day before and then that night, Spencer expected Derek to sleep in. But it seemed that Derek had other plans.

Spencer glanced at the dog laying at his feet, "Did you let Clooney out yet?" He asked.

"No." Derek shook his head.

Spencer climbed out of bed and stretched, "Let's go do that."

"Come on Cwooney." Derek called the dog over, "Good Doggy."

They let the dog out in the backyard. Derek wanted to wait by the door until they let the dog in, but they had things to do. Spencer wasn't just going to let him sit there for however long Clooney wanted to be outside.

"Are you hungry Der?" Spencer asked.

"Mhm." Derek nodded.

"Then we should go eat some breakfast."

"But waitin' for Cwooney." Derek pouted.

Spencer sighed, those puppy dog eyes were going to end up being the death of him, "I know, but Clooney wants to play outside for a little bit. He'll be fine while we're eating our breakfast."

Derek wasn't super happy with that answer but he was hungry, "Okay."

"Alright. Let's get some breakfast." Spencer smiled, holding out his hand for Derek to grab.

Derek followed Spencer into the kitchen. Spencer got Derek a bowl of cereal, as well as one for himself.

He wasn't sure if Derek wanted to feed himself or not, the boy hadn't even been certain what age he regressed to. He just let the kid feed himself. Spencer soon realized that letting Derek feed himself wasn't the best idea. Derek could get the food into his mouth at least, but not without making a mess.

"Derek, Buddy, can I feed you instead?" Spencer asked, hoping not to offend the boy.

Derek shrugged, "Okay."

Derek didn't really care if he fed himself or not, he was just hungry and wanted to eat his breakfast. He's a big boy, but that doesn't mean that Spencer can't feed him. Right?

Spencer set both of their bowls in the sink and turned to Derek, "Alright, I'll fill Clooney's bowl, you can let him back inside now."

"Okay Spencer." Derek smiled.

He ran off the back door to let his doggy inside. Clooney was excited about his breakfast but he stayed this Derek the whole way back to the kitchen. He didn't want Derek to be too far from him.

After letting Derek play with Clooney for a while Spencer decided that it was about time they got going, they had some shopping to do. It wasn't exactly easy to get Derek to put the dog back outside but not impossible, that pout almost made him bring the dog with them. With Clooney in the yard all it took was reminding Derek what they needed to go shopping for to get him into the car.

When they pulled into the store parking lot Derek got an icky feeling. He didn't like that feeling. Little Derek gets it a lot more than big Derek, but sometimes he gets is too and neither of them like it. That yucky nervous feeling, like he's about to mess up or someone's going to get hurt.

Derek didn't know how he felt about being little in public, it wasn't exactly noticeable, but it still made him a bit nervous. He couldn't just tell Spencer that he wanted to go home, they were already at the store and he told Spencer that it was okay. If he went home he'd have to wait to get little stuff and he really wanted some little stuff.

Derek held Spencer's hand and followed him through the store. It seemed a lot bigger and scarier now that he was regressed, but it was okay, because Spencer was there with him. Spencer made everything better, he always did.

Spencer didn't know for sure what Derek wanted so he decided they could start with the sippy cups, since they'd already discussed getting them. They stopped in the toddler and baby section to get the sippy cups and maybe some toys if Derek wanted them. Derek was to busy looking around, getting distracted by just about everything to actually notice the sippy cups.

"Which color?" Spencer asked.

Derek turned around to see what Spencer was looking at, there were lots of sippy cups in lots of colors, it was almost overwhelming, "Um... Red one."

Spencer nodded, setting it in the cart, "Alright. Any others?"

Derek looked over his options and pointed to another cup, "Bwue one."

"Okay Buddy." Spencer put the sippy cup in the cart and grabbed Derek's hand.

They didn't find much else that Derek wanted so they just did their grocery shopping as normal. On the way to the checkout they walked past the toy section. Spencer stopped when he saw Derek staring at the stuffed animals. He wished that Derek hadn't been too afraid to just ask. The boy was still too nervous about his little side to ask for something he wanted.

"Do you want one? You can pick one out." Spencer grabbed Derek's hand and gave it a gentle, reassuring squeeze.

Derek looked at Spencer, "Reawwy?"

"Of course Buddy." Spencer nodded, "If you see something you like, you're allowed to ask for it."

"Wan' the bunny." Derek happily grabbed a bunny dressed in a little vest.

"Why the bunny?" Spencer asked curiously.

"Cause he wooks wike you." Derek smiled, hugging the bunny.

"I look like a bunny to you?" Spencer raised an eyebrow at his regressed boyfriend.

"Yeah." Derek giggled.

"I don't think I look like a bunny."

"You do. See, cause you both wear vest wike dis and have brown hair, an' he probabwy reawwy smart wike you." Derek explained.

Spencer couldn't help but smile at his boy, "Okay. Why don't you put him in the cart and we can go pay."

Derek held on to his stuffed bunny the whole way home. He couldn't have been happier. Spencer was the best person in the whole world and Derek was so glad he had him.

**Author's Note:**

> If you have anything you want to see in this book or as a one shot in the series don't be afraid to let me know. If you have any feedback on my writing or the story feel free to tell me, I love hearing what you guy have to say.


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